Travelers in the Night Eps. 875 & 876: Newly Discovered Crater & Neighborhood Traffic

It's the 365 days of Astronomy Podcast coming in 3, 2, 1.

There are likely to be 2 million lunar impact craters, analysis of Mars orbiter images

with AI, has cataloged some 94 million Martian impact craters with diameters of 100 meters

or larger.

However, on our home planet, because of erosion by wind and water, and that three-quarters

of the world is covered with water, we have identified only about 200 impact craters.

Thus a paper entitled The Silver Bullet, New Evidence for a Hyper-Velocity Impact

Origin for the Silver Pit Crater, published in the journal Nature Communications, has stirred

up considerable interest among impact craters sleuths.

The Silver Pit Crater, discovered in 2002, is about 1.8 miles wide and lies some 766 yards

below the sea floor.

It is located in the North Sea approximately 80 miles from the Yorkshire coastline.

In their paper, Dr. Yusadine Nicholson, from Heret-Watt University and his team of nine co-authors,

analyzed 3D seismic imaging and drill cuttings from a 1980s oil well to make a convincing

case that the Silver Pit Crater was produced by the impact of a 1.5 football field diameter

asteroid approximately 45 million years ago.

The crucial piece of evidence is the presence of rare, shocked, quartz and fellspar crystals

only produced by the extreme temperatures and pressures of a hyper-velocity impact

at the same depths as the crater floor.

The event itself was an awesome natural spectacle caused when the asteroid traveling at 9 miles

per second slammed into the ocean floor, producing a mile high wall of rock and seawater

and a 30-story high tsunami.

Fortunately, asteroid hunters have not found a dangerous asteroid like this one heading

our way.

Now travelers in the night, this is Dr. Al Grower, stay tuned.

In a recent 60-day period, asteroid hunters tracked 24 space rocks which came closer than

our moon.

Half of them were smaller than a London double-decker bus.

The smallest has a diameter about the height of a human being, while the largest has a

diameter about three-quarters of the wingspan of a 747.

Two of them, both smaller than a compact car, came closer to humanity than the communication

satellites.

An object of their size enters the Earth's atmosphere every few months, creating a

light and sound show.

The largest and rarest visitor was 2025 RM1.

It has a diameter about half the size of a football field and was discovered by the

Atlas Group in Hawaii after it had passed about 60,000 miles from the Earth's surface.

According to the Earth Impact's calculator program, from the Imperial College of London

at Purdue University, an object of size of 2025 RM1 enters the Earth's atmosphere

approximately once every 460 years, begins to break up at an altitude of 222,000 feet

and burst into fragments at an altitude of about 44,000 feet.

It would not make a crater, but it is likely that large fragments traveling at three miles

per second would strike the surface.

It would create a spectacular light and sound event, a noise as loud as heavy traffic,

and an air blast that would likely shatter windows.

My team, the University of Arizona's Ketalina Sky Survey, operates five telescopes in the

mountains around Tucson, Arizona.

Our goal is to find objects like 2025 RM1, which are on an impact trajectory with our

home planet in advance, so that people in the affected area can be worn to stay away from

doors and windows.

For travelers in the night, this is Dr. Al Grower.

Stay tuned.

You are listening to the 365 Days of Astronomy Podcast.

The 365 Days of Astronomy Podcast is produced by the Planetary Science Institute.

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As we wrap up today's episode, we're looking forward to unraveling more stories from

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With every new discovery from ground-based and space-based observatories and each milestone

in space exploration, we come closer to understanding the cosmos and our place within

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Until next time, let the stars guide your curiosity.